Using birth and death records from 1950 to present day, a team of researchers in Scotland identified 28,540 women - whose body mass index (BMI) was recorded at their first antenatal visit - and their 37,709 offspring.

Relevant details about the pregnancy were collated, including the mother's age at delivery, number of previous pregnancies, mother and father's social class and infant sex, birth weight and gestation at delivery.

Among the mothers, 21 percent were overweight and 4 percent were obese. Among the 37,709 offspring there were 6,551 deaths from any cause. After adjusting for several factors, the researchers found a 35 percent increased risk of premature death in the adult offspring of obese mothers.

They also found a 29 percent increased risk of a hospital admission for a cardiovascular event in the adult offspring of obese mothers compared with offspring of mothers with normal BMI. The offspring of overweight mothers also had a higher risk of adverse events later in life.

It is thought that being overweight in pregnancy may cause permanent changes in appetite control and energy metabolism in the offspring, leading to a greater risk of heart problems later in life.

The findings highlight the urgent need for strategies to prevent obesity in women of childbearing age and the need to assess the offspring of obese mothers for their cardiovascular risk, the authors said.